Method and apparatus for trimming shaped plastic workpieces

ABSTRACT

A method and apparatus for laser trimming a shaped plastic workpiece use a laser beam positioned and directed by a robotic arm traveling along a pre-programmed path to trim the edges of a workpiece held against a positioning block. Preferably, the positioning block includes a laser beam capturing channel comprising suction holes for removing smoke generated by the ablation and burning of the plastic so as to minimize the risk of smoke damage to the workpiece and to remove soot and vapors from the work area. At the same time, laser beams are inhibited form reflecting back off the block onto the workpiece by positioning the channel under the workpiece and along the predetermined cutting path.

FIELD OF THE INVENTION

[0001] The present invention pertains to a method and apparatus fortrimming a shaped plastic workpiece such as a paint film laminate thatis to be used to form an injection molded automotive or truck part. Themethod uses a laser beam positioned and directed by a robotic arm alonga pre-programmed path to trim the edges of the paint film laminateworkpiece as the workpiece is held against a positioning block.

BACKGROUND OF THE INVENTION

[0002] A variety of injection molded parts are made and used forautomobile body and trim parts. For example, bumpers, spoilers, bodypanels, doors, filler panels, wheel covers, dashboards, arm rests andother parts are commonly made by the injection molding of thermoplasticmaterials.

[0003] In order to provide a painted or other decorative surface forinjection molded plastic trim parts, film lamination techniques arecommonly employed. A paint film laminate is insert molded or, as it issometimes referred to, co-molded, with the desired thermoplastic to fusethe film over the injection molded substrate. The resulting injectionmolded film-plastic part is ready for assembly without subsequentpainting.

[0004] The paint film laminate used in these insert molding techniquesmay comprise a backing sheet to which paint, other pigment-containing,or clear layers are adhered. Typically, the backing sheet comprises anextruded thermoplastic sheet. The paint or pigment layer may containcolored pigments or reflective flake pigments such as aluminum or micaflakes to provide for example a metallic finish.

[0005] The paint film may consist of a monocoat; a clear coat over abase coat; or a clear coat and a base coat with interposed print ordesign. The paint film, including base coat, clear coat and print ordesign, if desired, may range from about 0.5-4 mil. (13-100 μm) inthickness.

[0006] Laminated paint films are well known in the art and areavailable, for example, from Avery Dennison Decorative Films Div. ofSchererville, Ind., or Rexham Decorative Products of Charlotte, N.C. Forexample, laminated paint films are described in U.S. Pat. No. 5,514,427,the disclosure of which is incorporated herein by reference. The filmsare typically provided in a roll, unwound and then “preformed” to a sizeand shape approximating that of the final injection molded film-plasticpart.

[0007] The paint film laminate preform is next usually trimmed andplaced along the cavity side of an injection mold with the painted sideor “show” side thereof facing the mold cavity surface. Trimming may beaccomplished by hand or in some instances by the use of heavy stampingmachines that require the use of expensive tooling.

[0008] After trimming, the paint film laminate preform is ready for themolding process where it may be placed along the core side of the mold.The mold is then clamped and the desired molten resin is injected intothe mold cavity. Heat and pressure conditions in the mold partially meltthe backing sheet and a melt bonding or fusion of the injected resin andthe backing sheet of the film occur. Injection molds used for theseprocesses are rear or edge gated so that the molten resin is directedalong the backside of the film.

[0009] Techniques for preforming paint film laminates and insert moldingfilm-plastic parts are disclosed in U.S. Pat. Nos. 5,599,608; 5,759,477;and 5,783,287. The disclosure of these patents is incorporated herein byreference.

[0010] While the prior art process described above has proven effectivein many respects, there is a need in the art to improve upon thetrimming step for the paint film laminate so that this operation can beconducted economically and more accurately. At the same time, it isdesirable to minimize the use of heavy stamping or cutting machines thatrequire large spatial areas and expensive cutting tools and dies.

[0011] It is even more desirable to provide a laser trimming operationwherein operation of the laser is conducted in an enclosed atmosphere,shielding workers from the laser beam and from soot and vapors thatemanate from the cutting operation. Another desirable goal is to providean automated laser trimming apparatus wherein soot and vapors from thelaser cutting area are immediately removed from the trimming area to abag house or other filter mechanism and wherein the trimmed workpiecedoes not contain burned or charred areas surrounding the laser trimmingline.

SUMMARY OF THE INVENTION

[0012] These and other objects are met by the paint film laminatetrimming apparatus and process of the present invention. Basically, theapparatus comprises a rotatable wall carrying a work platform with theplatform including a plurality of convex positioning blocks mountedthereon. Each positioning block is contoured to correspond in shape anddimension to a desired work piece such as an automobile or truck trimpart.

[0013] In a first work station, the operator, which can include manualor robotic means, loads a plurality of “preformed” and roughly trimmedpaint laminate films over each of the positioning blocks. The roughlytrimmed paint films are dimensioned so that they snugly fit over thecorresponding positioning blocks. After all of these paint films areproperly positioned over their corresponding positioning blocks, thewall and associated platform are rotated to an enclosed work chamberwherein a laser performs a final, highly accurate trimming of the paintlaminate films.

[0014] In the laser cutting operation, X, Y, and Z coordinates of thedesired cutting pattern are contained in the memory of a microprocessor.The microprocessor then provides this information to a laser controllerwhich in turn moves the laser along the desired cutting pattern tofinally trim the paint film laminates, each of which is positioned onits associated positioning block.

[0015] The positioning blocks each include a plurality of suction portspositioned along the path of travel of the laser. These portscommunicate with a manifold and plenum chamber so that a suction sourcein operative association with the manifold and plenum chamber drawsparticulates and vapors from the laser cutting area to a bag house orother effective filter mechanism. This suction action also helps to gripor secure the paint film laminate to the positioning blocks.

[0016] The laser includes a source that generates a laser beam which isused to cut the workpiece along the path of travel. The projector is inoptical communication with the laser source, preferably through aflexible or jointed optical conductor, so that the projector receivesthe laser beam from the laser source and projects it onto the workpiecepositioned on one of the convex positioning blocks.

[0017] The robot positions and orients the projector to direct the laserbeam toward the convex positioning block and workpiece mounted thereon.A channel or groove is formed in the positioning block and extendssubstantially parallel to the desired cutting line. The laser photonspass through the workpiece providing a clear cut therein and thenterminate in the channel without reflecting out of the channel onto theback of the workpiece.

[0018] Most preferably, the robot includes a first arm or spar havingproximal and distal ends. The spar includes a wrist portion near itsproximal end on which the projector is mounted. The robot also includesa second arm or boom having a proximal end pivotally supported by abase. The boom has a distal end near which the boom pivotally supportsthe proximal end of the spar.

[0019] The controller electrically communicates with robot electricmotors positioned near the wrist portion as well as near the proximalends of the spar and the boom to enable the robot to move the projectorso that the laser beam traces the path of travel programmed into thecontroller. Most preferably, the controller signals the robot electricmotors to orient the projector so that the laser beam remains normal tothe tangent of the path of travel and maintains a constant angle with aplane containing that path as the laser beam traces the path.

[0020] The invention will be further described in conjunction with theattached drawings and in the ensuing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a side elevational view of a rotatable laser cuttingunit according to the present invention;

[0022]FIG. 2 is a perspective view of a convex positioning block for thelaser cutting unit of FIG. 1, partially cut away along the line 2-2 inFIG. 1 to show suction ports opening through the surface of the block;

[0023]FIG. 3 is a schematic view showing a laser projector for use withthe laser cutting unit of FIG. 1 mounted on a robotic arm;

[0024]FIG. 4 is a schematic view of the laser projector of FIG. 3trimming a paint film laminate workpiece;

[0025]FIG. 4a is a magnified schematic view of the cutting area showingthe laser photons cutting the workpiece and then terminating in thechannel formed in the positioning block;

[0026]FIG. 5 is a block diagram showing the preferred system forcontrolling the movement of the laser in accordance with the invention;

[0027]FIG. 6 is a partially cut away top plan view showing the rotatablewall and work platform in the open or loading position wherein theoperator may manually load pretrimmed paint film laminate parts onto thepositioning blocks; and

[0028]FIG. 7 is a partially cut away top plan view showing the rotatablewall and work platform positioned in the safety enclosure ready foroperation of the laser-trimming position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0029] As shown in FIG. 1, a laser cutting unit 10 in accordance withthe invention includes a metallic work platform 16 carrying a pluralityof convex positioning blocks 22, 24, 26, 28, 30 and 32 thereon. The workplatform 16 is attached to rotatable wall 40 by horizontal truss members42, 44 with mounting brackets 52, 54 respectively formed in the trussesfor fixed mounting of the bottom portion of work platform 16 therein.

[0030] The work platform 16 and wall 40 may be rotated by rotatableshaft 60 that is driven by electric motor 62. As shown in FIG. 1, theproximal ends of the trusses 42, 44, in this position, rest uponstationary legs 46, 48 that are in turn fixed to stationary base 50.Accordingly, the entire wall 40, associated work platform 16, andtrusses 42, 44 are positioned for rotation between: (1) a loading andunloading station and (2) a laser trimming station, as shall beexplained hereinafter.

[0031] The unit 10 includes an air manifold 20 (best shown in FIG. 2)formed by the interior housing of platform 16. The manifold communicateswith chamber 70, with both the manifold and chamber being operativelyconnected to a vacuum source (not shown). Air, gases and soot that arepresent near the platform are drawn via the action of the vacuum source,through the manifold and chamber to a bag house or other air cleaningdevice (not shown).

[0032] Each of the convex positioning blocks 22, 24, 26, 28, 30, 32 hasan outer contour complementary to the contour of the concave workpiece80 which it is desired to trim. As shown in FIG. 2, the block 22includes a peripheral groove 90; a series of hold down ports 92 and aseries of suction ports 94 communicating with a plenum 96, the manifold20 and ultimately with chamber 70. Each convex positioning block 22, 24,26, 28, 30, 32 is provided with an associated plenum 96 that in turncommunicates with the manifold 20.

[0033] The hold down ports serve primarily to secure the workpiece 80against the block 22. The suction ports 94 serve primarily to draw gasesand soot evolved from the burning or ablation of the workpiece 80 intothe plenum 96. The suction ports 94 preferably are larger in diameterthan the hold down ports 92 so as to draw a greater volume flow of airfrom into the plenum 96 from the vicinity of the groove 90.

[0034] When the rotatable wall and associated work platform are rotatedto the laser trimming station, the workpiece 80 is trimmed by means of alaser beam which is generated by a laser source 110 (FIG. 3) andprojected against the workpiece 80 by means of a projector 112 (FIG. 3).As shown in FIG. 3, the projector 112 is mounted on a robot 114. Therobot 114 is programmed to move the projector 112 so that the laser beamprojected by the projector 112 traces a path of travel near theperiphery of the workpiece 80.

[0035] The preferred laser source 110 is a 200 W laser available fromSynrad, Inc. of Mukilteo, Wash. Preferably, the source 110 itselfremains stationary on a shelf (not shown) positioned above the lasercutting unit 10 (FIG. 1). The laser beam generated by the source 110 istransmitted to an optical conduit 120 which, in turn, conducts the beamto the projector 112. The optical conductor 120 includes a series ofpivotally coupled sections 122, 124 and 126 which allow the robot 114 totranslate and re-orient the projector 112 so as to direct the laser beamonto the workpiece 80 (FIG. 2).

[0036] The preferred robot 114 is available from FANUC Robotics Corp. ofAuburn, Mich. It includes a spar or first robotic arm (shown in phantomat 130) having a proximal end 132 and a distal end 134. A wrist portion136 near the distal end 134 of the spar 130 supports the projector 112for pivotal movement around a first pivot axis 138 and a second pivotaxis 140. The robot 114 also includes a boom or second robotic arm 150(shown in phantom) having a proximal end 152 and a distal end 154. Theboom 150 supports the proximal end 132 of the spar 130 near its distalend 154 for pivotal movement around a third pivot axis 156. In addition,the robot 114 includes a base 160 (shown in phantom) which supports theproximal end 152 of the boom 150 for pivotal movement around a fourthpivot axis 162 and a fifth pivot axis 164, which intersect at a pivotpoint 166.

[0037] The wrist portion 136 includes a pair of blocks 170 and 172; alink 174; a first robot electric motor 176; a yoke 178 affixed to thespar 130 and a second electric motor (shown schematically at 180). Theprojector 112 is directly supported by the block 170. The blocks 170,172 are connected by the link 174 eccentrically to the first pivot axis138. The block 172 is mounted on a drive shaft (not shown) of the firstrobot electric motor 176 so as to cause the first robot electric motor176 to pivot the projector 112; the blocks 170, 172; and the link 174 asa unit relative to the first pivot axis 138. The projector 112 itselfincludes an elbow 190 to direct the laser beam at an angle transverse(preferably perpendicular) to the first pivot axis 138.

[0038] The first robot electric motor 176 itself is supported by theyoke 178. The second robot electric motor 180 is housed within the yoke178 so as to enable the second robot electric motor 180 to pivot thefirst electric motor 176 (and the direction of the first pivot axis 138)relative to the second pivot axis 140.

[0039] A third robot electric motor (shown schematically at 200) ishoused within the distal end 154 of the boom 150 to cause the spar 130to pivot relative to the third pivot axis 156. Fourth and fifth robotelectric motors (shown schematically at 202 and 204) are housed withinthe base 160 to cause the boom 150 to pivot relative to the fourth andfifth pivot axes 162, 164, that is, relative to the pivot pint 166.

[0040] A controller 210, which is preferably a microprocessor, is inelectrical communication through means well known to those of ordinaryskill in the art with the robot electric motors 176, 180, 200, 202, 204so as to induce the robot electric motors 176, 180, 200, 202, 204 tomove the projector 112 so that the laser beam traces a path of travel(212 in FIG. 4) programmed into the controller 210.

[0041] Referring next to FIG. 4, a preferred method for trimming aplastic workpiece 80 begins by mounting the workpiece 80 on one or moreof the convex positioning blocks (only block 22 shown in FIG. 4) so thepath 212 along which the workpiece 80 is to be trimmed lies adjacent theperipheral groove 90. At least a partial vacuum is drawn through theplenum 96 (FIG. 2) and the hold down ports 92 (FIG. 2) of the block 22to secure the workpiece 80 to the block 22. Next, the path of travel 212is programmed into the controller 230 (FIG. 3). The controller 230induces the robot electric motors 176, 180, 200, 202, 204 to move theprojector so that the laser beam traces the path of travel 212 toseparate a first portion 214 of the workpiece 80 from a second (scrap)portion 216. Preferably, the laser beam is directed normally to atangent of the path of travel 212 and at a constant angle with the planeof the work platform 16. As the laser beam cleanly cuts the workpiece80, gases and soot generated by the process are removed through thesuction ports 94 (FIG. 2). When the first and second portions 214, 216of the workpiece 80 have been completely separated, the vacuum drawnthrough the plenum 96 is released so that the first portion 214 of theworkpiece 80 can be removed.

[0042]FIG. 4A schematically depicts another important aspect of theinvention and shows an example of how the invention helps to minimizeburned or charred areas that in some prior art methods may be left alongthe laser cut line. Here, the laser beam L is shown penetrating theworkpiece 80, typically a paint film as the film is positioned over theblock 22. The laser beam impinges on the film at an approximate rightangle, passes through the workpiece to provide a clean cut, and extendsinto the depth of the peripheral groove 90 formed in block 22. The depthof the groove 90 is dimensioned so that the photons or beams L aretotally captured within the groove 90 and do not rebound off the block22 back into the underside of the workpiece 80. In contrast, in someprior art methods that do not employ a photon capturing groove 90contiguous to the cut line, the laser photons bounce off a backgroundsubstrate and re-enter the workpiece adjacent the cut line resulting incharring or burning of the part.

[0043]FIG. 5 provides a simplified block diagram showing the manner inwhich the laser is ultimately driven along the desired path to performits accurate cutting operation on the plurality of paint film laminateworkpieces each of which is positioned on its associated convexpositioning block.

[0044] In accordance with conventional techniques, X, Y, and Z cuttingcoordinates for the desired cut or trim are provided as input and aredigitized. This information is fed as memory to a microprocessor unitthat, in turn, provides this information to controller 210 that in turnprovides drive input for motors 176, 180, 200, 202, 204 (see FIG. 3).

[0045] The manner in which the laser drive is controlled is not anessential part of the invention and, accordingly, the provision ofcoordinates for the desired cutting pattern and correlated laser drivecan be provided by a variety of conventional techniques. Examples ofsuitable laser control methods are detailed for example in U.S. Pat.Nos. 5,698,121 (Kosaka et al.); 4,918,611 (Shyu et al.) and 5,466,909(Nihei et al). The disclosures of these patents are incorporated byreference herein.

[0046]FIGS. 6 and 7 illustrate a preferred embodiment of the inventionin which the wall 14, associated platform 16 and support trusses 42, 44can be rotated between: (1) a loading and unloading station and (2) thelaser trimming station with operation at the laser trimming stationproceeding as set forth above. With reference first to FIG. 6, the wall14 and associated platform 16 are positioned at the loading andunloading station 526. As shown, the assembly is housed by said wallmembers 502, 504 and end wall member 506, the latter of which definesthe end-wise boundary for the laser trimming station 524. The housing isopen ended at the loading and unloading zone 526. Roof 510 extends overthe assembly from the middle of the side walls to the end wall 506.Accordingly, a closed chamber is provided in the laser trimming station524. In FIGS. 6 and 7, the roof member 510 is partially broken away.This is necessary to reveal the positioning of the wall and platform inthe laser trimming station 524 shown in FIGS. 7 and 8.

[0047] In accordance with the inventive methods, the wall 14, platform16 and associated trusses 42, 44 are first caused to rotate so that theplatform 16 is presented in the position shown in FIG. 6. Here, anoperator places the preformed and roughly trimmed paint film laminateworkpieces over the corresponding convex positioning blocks that aremounted on the work platform. Then, the platform 16 and its associatedsupport mechanisms including the wall 14 and trusses 42, 44 are rotatedso that the platform 16 is positioned in the laser trimming station 524with, as aforementioned, the laser trimming station being enclosed bywall members 502, 504, 506 and roof 510.

[0048] While in the enclosed chamber, the laser cutting of the paintfilm laminate workpieces is performed. As aforementioned, gases andparticulates are drawn through the positioning blocks through manifold20 and chamber 70 to a bag house or other air cleaning station.Accordingly, the entire laser cutting operation is performed in anenclosure so as to shield the work force from the laser beam and thegases and particulates that are formed as an undesirable byproducts ofthe cutting operation.

[0049] After the laser cutting operation is performed, the platform 16and its associated support mechanisms are rotated back to the positionshown in FIG. 6. The operator then unloads the accurately dimensionedlaser cut workpieces from the platform, and provides preformed roughlytrimmed workpieces over the positioning blocks so that the precise lasertrimming cycle can be again commenced.

[0050] While this invention has been described with respect toparticular embodiments thereof, it is apparent that numerous other formsand modifications of this invention will be obvious to those skilled inthe art. The appended claims and this invention generally should beconstrued to cover all such obvious forms and modifications which arewithin the true spirit and scope of the present invention.

1. A method of trimming a paint film laminate workpiece to correspond topredetermined dimensions comprising: a) placing said paint film laminateon a work platform; b) trimming said laminate to said predetermineddimensions; and c) venting volatiles and particulates that may be formedby said trimming away from said work platform.
 2. A method as recited inclaim 1 further comprising providing a port proximate said workplatform, and wherein said venting comprises applying a source ofsuction through said port to thereby vent said vapors and particulates.3. A method as recited in claim 2 wherein said trimming comprisescutting said laminate with a laser.
 4. A method as recited in claim 3wherein said work platform comprises a convex shaped positioning block,said block having said port mounted therein.
 5. A method of trim cuttinga thin film laminate work piece comprising: a) placing said thin filmlaminate on a work platform; b) moving said platform to an enclosedhousing; and c) laser trimming said laminate along a predeterminedcutting path to predetermined dimensions while in said enclosed housing,and d) providing a laser beam capturing groove adjacent said cuttingpath and under said thin film laminate.
 6. Method as recited in claim 5further comprising d) venting volatiles and particulates from said lasertrimming step.
 7. Method as recited in claim 6 further comprisingventing said volatiles and particulates through said groove.
 8. Methodas recited in claim 7 further comprising moving said platform after saidlaser trimming step c) to an unloading station.
 9. Method as recited inclaim 8 further comprising placing apertures in said platform incommunication with said channel.
 10. Method as recited in claim 9further comprising providing a convex positioning block on said workplatform, said apertures provided in said positioning block and whereinsaid placing a) comprises placing said thin film laminate on saidpositioning block.
 11. A method for trimming a workpiece defining aconcave workpiece contour, said method comprising the steps of: a)positioning said workpiece on a convex positioning block having a blockcontour complementary to said workpiece contour; b) projecting a laserbeam onto a surface of said workpiece to trim said workpiece; c)providing suction ports in said convex positioning block; and d) drawingat least a partial vacuum through suction ports to vent particulates andvolatiles away from said workpiece.
 12. A method for trimming aworkpiece defining a concave workpiece contour having a re-entrantsection, said method comprising the steps of: a) positioning saidworkpiece on a convex positioning block, said positioning block having agroove; b) programming a controller to define a path of travel lyingproximate said groove; c) positioning a projector to direct a laser beamonto said workpiece at said home position on said path of travel; d)moving said projector to induce said laser beam to trace said path oftravel on said workpiece; and e) drawing at least a partial vacuumthrough suction ports communicating with said groove.
 13. Apparatus fortrimming a paint film laminate workpiece to correspond to apredetermined dimensional configuration, comprising: a) a work platformhaving said workpiece mounted thereon; b) trimming means in operativeassociation with said work platform for cutting said laminate so thatsaid laminate corresponds to said predetermined dimensionalconfiguration; c) a channel communicating with said work platform; andd) means for drawing a draft through said channel to thereby ventparticulate and volatiles that may be formed by said trimming means b)away from said work platform.
 14. Apparatus as recited in claim 13wherein said platform comprises a convex positioning block and whereinsaid laminate is placed on said positioning block, said block comprisingat least one opening therein in communication with said channel. 15.Apparatus as recited in claim 14 wherein said trimming means b)comprises a laser cutting.
 16. Apparatus as recited in claim 13 furthercomprising means for moving said platform to an enclosed housing andwherein said trimming means b) is located in said enclosed housing. 17.Apparatus for trimming a workpiece comprising: a convex positioningblock for positioning the workpiece thereon, said convex positioningblock having a block contour complementary to a contour of saidworkpiece; a projector for directing a laser beam onto the workpiecewhen the workpiece is positioned on said positioning block; a roboticarm having a distal end, said projector being supported near a distalend of said robotic arm for movement along a path of travel; and aprogrammable controller for inducing said robotic arm to move saidprojector so that said laser beam traces said path of travel.
 18. Theapparatus as recited in claim 17 wherein said positioning block includesa vacuum source for drawing at least a partial vacuum and a plurality ofsuction ports communicating with said vacuum source, said plurality ofsuction ports being arranged along said path of travel.
 19. Theapparatus as recited in claim 17 wherein said positioning block isconvex, defining a groove along said path of travel for receiving are-entrant portion of said workpiece; and wherein said suction portsopen through said groove.
 20. The apparatus as recited in claim 17wherein said positioning block includes a plurality of hold-down portspositioned within said path of travel and communicating with said vacuumsource, each of said suction ports being larger than any of saidhold-down ports.
 21. The apparatus as recited in claim 17 including alaser light source and an optical conduit for conducting laser lightbetween said optical source and said projector.
 22. The apparatus asrecited in claim 17 including a wrist portion supported near said distalend of said robotic arm for rotatably mounting said projector.
 23. Theapparatus as recited in claim 17 including a boom pivotally mountingsaid robotic arm.
 24. The apparatus as recited in claim 23 including abase pivotally mounting said boom.
 25. The apparatus as recited in claim17 wherein said controller is a microprocessor electricallycommunicating with a plurality of electric motors for controllingmovement of said robotic arm and said projector.
 26. Apparatus fortrimming a concave plastic workpiece comprising: a convex positioningblock having a block contour complementary to a workpiece contour; saidconvex positioning block defining a plenum and a plurality of hold-downports communicating with said plenum; a vacuum source communicating withsaid plenum for drawing at least a partial vacuum through said hold-downports; a laser source for generating a laser beam; a projector opticallycommunicating with said laser source for directing said laser beamtoward said convex positioning block; a spar defining a spar proximalend and a spar distal end; a wrist portion mounted near said spar distalend, said wrist portion including a first robot electric motor forpivoting said projector along a first pivot axis and a second electricmotor for pivoting a direction of said first pivot axis; a boom having aboom proximal end and a boom distal end, said boom pivotally supportingsaid spar proximal end near said boom distal end; a third robot electricmotor for pivoting said spar relative to said boom; a base pivotallymounting said boom proximal end; a fourth robot electric motor forpivoting said boom relative to said base; a fifth robot electric motorfor pivoting said boom relative to said base; and a controllerprogrammed to recognize a path of travel along said convex positioningblock, said controller being in electrical communication with saidfirst, second, third, fourth and fifth robot electric motors to inducemovement of said projector so that said laser beam traces said path oftravel; said convex positioning block including a groove extending alongsaid path of travel and a plurality of suction ports communicatingbetween said plenum and said re-entrant groove, said suction ports beinglarger than said hold-down ports.
 27. Apparatus for trimming a pointfilm laminate workpiece along a predetermined cutting path, comprisinga) a work platform adapted for mount of a workpiece thereon; b) laserbeam trimming means in operative association with said work platform forcutting said workpiece along said predetermined path; and c) a channeladjacent said predetermined path and underneath said workpiecedimensioned to capture laser beams cutting through said workpiece whileinhibiting reflection of said laser beam from said work platform ontosaid workpiece.